Nasir, whose birthday is Jan. 29, died Thursday after Milliner's boyfriend hit him several times in the torso with his fist, shoulder, head and forearm, then dropped him on a kitchen floor, Hillsborough County sheriff's deputies said.

Derron Denard Brown, 24, was arrested Friday on first-degree murder and aggravated child abuse charges. He is being held without bail in the Hillsborough County jail.

On Saturday, Milliner picked out a photo to use at the funeral. She talked about Nasir's favorite teddy bear and clutched a soft, stuffed cat he had held the night before. She pointed out the stain from where he had put his mouth on it, full of food.

It's one of the last memories she has of her son.

Milliner left Nasir with Brown at her North Tampa apartment for a short time Thursday morning, deputies said.

When she returned, Milliner found her son unresponsive. Paramedics rushed Nasir from his home near Fletcher Avenue and Interstate 275 to Florida Hospital Tampa, where he later died.

The little boy with dark hair and brown eyes was just beginning to grow up, his mother said.

"He had been standing up and just starting to walk," she said. "He had finally started saying 'Mama.' "

He was a quiet baby, who behaved best when by his mother's side, Milliner said.

When she left home Thursday, Milliner said, she only dropped her 4-year-old son at preschool and came right back. She arrived to find Brown lying in bed, "like nothing happened," she recalled.

She checked on Nasir but didn't see any bruises or marks right away.

"He was laying there looking like he was asleep, but wouldn't wake up," she said.

Brown, she said, has a 5-year-old daughter and lives in an adjacent apartment with his mother, but sometimes spent the night with her. He had watched her children in the past while she worked and everything had been fine, she said. They had been dating for about seven months.

"He never showed any sign he would do something like this. …I just want to get in his face and ask him, 'Why? What did you do to Nas?' " Milliner said.

Detectives told her that Brown described how he "tackled my son, punched him, took him to the kitchen and dropped him on the floor," she said. He told detectives he then held and tried to comfort Nasir, who only cried for two minutes, before putting him in a bed, according to Milliner.

The Hillsborough County Medical Examiner's Office determined Friday that Nasir died from blunt trauma to the torso with liver laceration, deputies said. The death was ruled a homicide.

Milliner has cooperated with the Sheriff's Office during the investigation, deputies said.

Prior to Nasir's death, the Florida Department of Children and Families had no involvement with the family, spokeswoman Terri Durdaller said. The agency removed another child from the home due to the death, she added.

Brown, of Sand Lake Circle, has one previous arrest in Florida, state records show. Tampa police arrested him on burglary and criminal mischief charges in 2008. Brown pleaded guilty in 2010 after the burglary charge was reduced to trespassing. A judge ordered him to serve six months on probation. Brown also pleaded guilty to criminal mischief and was sentenced to a month in jail in April.

Times researcher John Martin contributed to this report. Shelley Rossetter can be reached at srossetter@tampabay.com or (813) 661-2442.